The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the electronics industry utilized programmable memory elements in various electronic systems for many different types of applications. Some programmable memory elements lost stored information if the memory element was not periodically refreshed. An erasable programmable read-only memory (EPROM) is one example of such a non-volatile memory. One problem with an EPROM is reliability. The reliability of information stored in the EPROM diminishes with the length of time that the EPROM is in operation with power applied. Typically, the EPROM was periodically refreshed in order to increase the reliability. However, separate sense amplifiers and other circuitry typically were required in order to provide the required refresh operations and also to perform a read operation of the programmable memory element. These separate sense amplifiers and circuitry increased the size of a semiconductor die that contained the programmable memory element thereby increasing the cost. The separate sense amplifiers and circuitry also consumed power thereby increasing the power consumption of the semiconductor die.
Accordingly, it is desirable to have a method of forming a programmable memory element that does not decrease reliability with the operating lifetime, that does not require periodic refreshing, and that does not require separate sense amplifiers and associated circuitry.